This might help people with the same problem.
In a previous post, I was telling that Flex builder could not
connect to the debugger.
After long searches on the net, I found an article with the
This is due to my anti-virus, NOD32 who blocks the
To make things work again, go in the configuration pages of
NOD32, http/Web brower, and untick the checkmark of the web browser
used for debugging.
And it works!